Pixel non-uniformity correction system
US4602291A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 9, 1984 |
| Grant date | Jul 22, 1986 |
| Priority date | — |
| Expiry date | May 9, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N25/671
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A solid state imager wherein a pixel non-uniformity correction system compensates for photosite non-uniformities by providing a linear correction method and utilizing three modes: mode #1--dark current detection, mode #2--uniform illumination, and mode #3--data detection mode. In the first calibration cycle, the outputs of all the photocells on an imager 10, representing "dark current" are stored in an "offset" memory 14. In the second calibration cycle, a uniform illumination from a constant light level is applied to the imager 10. This uniform illumination signal is passed to an arithmetic unit 18 where the dark current signal is subtracted from it and the difference is then stored in gain memory 28. The gain memory passes this signal back to the arithmetic unit 18, so that in the third mode, the data detection mode, the arithmetic unit 18 can electronically correct the data signals that were non-uniformly affected by the internal characteristics of the imager.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.